1. Field of the Invention
The present invention relates to a sampling die for taking samples from a bulk powder and a press for compacting the powder in the die into a tablet or caplet form.
2. Description of The Related Art
In the pharmaceutical industry, solid pharmaceutical dosage forms such as tablets, capsules, and caplets are manufactured from a blend of active and inactive ingredients in powder form. The active and inactive ingredients are blended together in a special blender or mixer. When the blended powder is stored after blending, there is a tendency for the dry powders of the active ingredient(s) and the inactive ingredient(s) to segregate or separate, resulting in non-uniform distribution of the active ingredient(s) in the finished product. Therefore, before further processing of such blends, bulk samples are taken from different places in these blends and analyzed to check whether or not the active ingredients are uniformly distributed. Such a test is known in the trade as a content uniformity test or a homogeneity test, and requires unit-dose samples with sample sizes equal to about one dose of the product taken from different locations within the powder blend. Usually, samples of the powder blend must be transferred from the storage area to the laboratory for analysis. As a powder sample is transported some powder grains may get blown off. In addition, as the powder sample is transferred from one container to another, or from a container to a balance and vice versa, some of the powder will adhere to the container such that the sample which arrives at the laboratory for analysis may not be equivalent to a single dose as was measured when the sample was taken or immediately thereafter. To minimize this type of sampling error, the need exists in the art for an apparatus that allows the powder sample to be compacted, in the same container with which the sample was taken, into a solid tablet or caplet immediately after the sample is taken. Examples of presses for compaction of powders can be seen among the references cited below. However, none of the references cited below show a press adapted to compact powder within a die that can also serve as a sampling container. Further, none of the cited references show a die that is designed to serve both as a mold for compacting a powder sample into a tablet or caplet and as a container for sampling the powder that is to be compacted.
U.S. Pat. No. 4,411,848, issued to Raymond P. DeSantis on Oct. 25, 1983, is directed to a press for compacting powder material. The press of DeSantis uses a piston having a large diameter and a small diameter end to generate an amplified pressure in a hydraulic circuit in response to the pressure applied to a pneumatic circuit.
U.S. Pat. No. 3,274,303, issued to Werner Muller on. Sep. 20, 1966, is directed to a press for compressing a magnetizable powder to form a permanent magnet. The press of Muller has a mold or die that is open at both ends. Upper and lower punches cooperatively compress the magnetizable powder within the mold. The mold has integral magnetizing windings.
U.S. Pat. No. 4,781,567, issued to Henry A. Miller, Jr. on Nov. 1, 1988, is directed to an apparatus for evaluating the compaction properties of a medicinal powder. The apparatus of Miller uses a die that is open at both ends. A sliding anvil is used to block one end of the die and a tamping pin compresses the powder in the die from the other end of the die. The anvil has a hole that can be brought into registry with the die to eject the compressed powder.
U.S. Pat. No. 3,790,330, issued to Charles H. Roland on Feb. 5, 1974, is directed to a compaction press for compressing a powder by pressing the powder in a mold using a movable piston. The plate sealing the bottom of the mold has the plunger which is used to break up the compressed powder before repressing the powder.
U.S. Pat. No. 4,880,373, issued to Stephen Balog et al. on Nov. 14, 1989, is directed to a compaction press for compressing a powder. The press of Balog et al. uses a die which is split vertically. Also, the press of Balog et al. has both a vertical and a horizontal pressure applying means. The horizontal pressure applying means holds the die together while the vertical pressure applying means compresses the powder in the die.
U.S. Pat. No. 5,417,903, issued to Roger G. Harrison et al. on May 23, 1995, is directed to a manually operated pill press. The pill press of Harrison et al. has a storage compartment for holding a supply of powder, a blind mold cavity, and a pill ram for compressing powder within the mold cavity. The pill ram also serves to extract the formed pill from the mold cavity.
U.S. Pat. No. 3,659,985, issued to Alec Frank Marshall et al. on May 2, 1972, is directed to a press for compacting metal powders. The press of Marshall et al. has a die with a passage which extends through the entire length of the die and requires both a lower punch and an upper punch to compact a quantity of powder. U.S. Pat. No. 3,775,032, issued to Joseph E. Smith et al. on Nov. 27, 1973, also shows a powder compaction apparatus requiring both a lower punch and an upper punch. Similarly, U.S. Pat. No. 3,788,787, issued to Hermann Silbereisen et al. on Jan. 29, 1974, and U.S. Pat. No. 4,061,453, issued to Raymond P. DeSantis on Dec. 6, 1977, show further examples of powder compaction apparatuses requiring both a lower punch and an upper punch. U.S. Pat. No. 4,408,975, issued to Adolf Hack on Oct. 11, 1983, shows a tablet making press having a plurality of upper punches and lower punches.
U.S. Pat. No. 4,684,101, issued to Earl F. Wagner et al. on Aug. 4, 1987, is directed to an injection molding mold having an insert which defines in part the mold cavity and which is readily accessible for replacement from the side of the mold.
U.S. Pat. No. 5,004,413, issued to Douglas R. Stopforth on Apr. 2, 1991, shows a tablet making press having a plurality of upper punches and lower punches carried on a rotor. The rotor also carries a die plate having a die for each set of upper and lower punches. As the rotor rotates, the punches are moved by cam surfaces to compress powder in the dies into pills.
U.S. Pat. No. 5,158,728, issued to Richard Sanderson et al. on Oct. 27, 1992, shows a tablet making press for making a tablet from two distinct powder formulations. The Sanderson et al. press has a plurality of upper and lower punches which are moved in and out of dies by upper and lower cam assemblies.
Soviet Document Number 07681 by E. A. Petrov, dated Dec. 22, 1967, Soviet Document Number 409789 by the Voronezh Press Construction Bureau, dated May 21, 1974, and Japanese Published Application Number 3-181326, dated Aug. 7, 1991, all show further examples of powder compaction apparatuses requiring both a lower punch and an upper punch.
Japanese Published Application Number 60-37298 by Takeshi Katagiri, dated Feb. 26, 1985, shows a powder compaction press having a lower punch which compacts powder in a die against an upper plate which is integral with the press.
U.S. Pat. No. 444,887, issued to Carles J. Menges on Jan. 20, 1891, and United Kingdom Patent Specification Number 1,077,122 by George Ernest Alsop, dated Jul. 26, 1967, show sampling probes having an outer barrel with a penetrating tip and an opening near the penetrating tip. An inner rod is attached to a sampling receptacle located near the penetrating tip. The inner rod can be rotated to bring the opening of the sampling receptacle into or out of alignment with the opening in the outer barrel.
U.S. Pat. No. 1,078,847, issued to Wilhelm Grauenfels et al. on Nov, 18, 1913, and U.S. Pat. No. 3,080,760, issued to Henry D. Piersma on Mar. 12, 1963, show sampling probes having an outer barrel with a penetrating tip and a plurality of openings distributed along the length of the outer barrel. An inner rod has a plurality of sampling receptacles distributed along its length. The inner rod can be rotated to bring the sampling receptacles into or out of alignment with the openings in the outer barrel.
U.S. Pat. No. 1,168,486, issued to Leonard H. Des Isles on Jan. 18, 1916, shows a sampling probe having a plurality of sampling containers tied together in series by pieces of string. The first sampling container has a penetrating tip which at its base is larger in diameter than any of the sampling containers. The sampling containers are placed in an elongated tube with the penetrating tip acting as a closure for one end of the tube. A long line attached to the sampling receptacle farthest from the penetrating tip is used to keep the pieces of string between the sampling receptacles taught as the sampling probe is plunged into a bulk quantity of granular material. Once the sampling probe reaches the desired depth, then the elongated tube is removed allowing the sampling receptacles to fill with the granular material.
U.S. Pat. No. 3,091,969, issued to Steve Romanchuk et al. on Jun. 4, 1963, shows a powder metal sampling device in the form of a rectangular parallelepiped having a plurality of oblique cavities distributed along its length.
U.S. Pat. No. 3,696,974, issued to Germaine Van der Veken on Oct. 10, 1972, shows a liquid sampling device having an inner member slidably supported by an outer member. The inner member has a sampling receptacle which is exposed when the inner member is extended relative to the outer member. The sampling receptacle is closed off when the inner member is retracted relative to the outer member.
U.S. Pat. No. 5,337,620, issued to Sanyasi R. Kalidindi on Aug. 16, 1994, and U.S. Pat. No. 5,440,941, issued to Sanyasi R. Kalidindi on Aug. 15, 1995, show sampling probes having an outer barrel with a penetrating tip and an inner rod capable of holding a plurality of sampling dies. The outer barrel has a plurality of openings which expose the sampling dies when the inner rod is turned to the appropriate position relative to the outer barrel. Kalidindi ""620 and Kalidindi ""941 use different types of sampling dies than those disclosed herein. Further, the inner rods of Kalidindi ""620 and Kalidindi ""941 are not adapted to allow the removal of the sampling dies in the same manner as in the present invention.
None of the above inventions and patents, taken either singularly or in combination, is seen to describe the instant invention as claimed. Therefore, the need persists for a sampling die which can also serve as a molding die for compacting a powder and for a press for compacting the powder sample contained within such a sampling die.
The present invention is directed to a die that is designed to serve both as a mold for compacting a powder sample into a tablet or caplet and as a container for sampling the powder that is to be compacted. The die is made in two pieces. The top piece of the die has a passage extending through the thickness of the top piece. The bottom piece of the die acts as a removable closure for the bottom opening of the passage in the top piece in order to form a mold cavity. The present invention also includes a press adapted for compacting a powder sample contained within the mold cavity of a die which serves both as a sampling container for the powder and as a mold for compaction of the powder.
Accordingly, it is a principal object of the invention to provide a die which serves both as a sampling container for a powder and as a mold for compaction of the powder.
It is another object of the invention to provide a die which can serve as a mold for the compaction of a powder sample and which is adapted to fit into a sampling probe designed for insertion into a bulk powder.
It is a further object of the invention to provide a two-piece die having a bottom piece which can be removed to allow the ejection of the final product from the die.
Still another object of the invention is to provide a press adapted for compacting a powder sample contained within the mold cavity of a die which serves both as a sampling container for the powder and as a mold for compaction of the powder.
It is an object of the invention to provide improved elements and arrangements thereof for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes.